Fabrication and excellent performances of Bi0.5Sb1.5Te3/epoxy flexible thermoelectric cooling devices

How to fabricate flexible thermoelectric (TE) films with excellent electrical transport properties remains a major bottleneck for high-performance flexible TE cooling devices. Herein, a simple and efficient method is developed to fabricate high-performance flexible TE cooling device by selecting Bi0.5Sb1.5Te3 as TE component and epoxy resin as adhesive. It is discovered that the (000l) preferential orientation of Bi0.5Sb1.5Te3 grains could be successfully realized in Bi0.5Sb1.5Te3/epoxy thick films by hot-pressing curing process, thus causing the remarkable enhancement in the electrical transport properties. The highest power factor of the (000l)-oriented Bi0.5Sb1.5Te3/epoxy thick films reached 0.84 mW m−1 K−2 at 300 K, increased by 250% and 223% as compared with that of our non-pressure thick film and the highest value by other groups, respectively. A prototype flexible TE cooling device had been fabricated with the Bi0.5Sb1.5Te3/epoxy thick films. The stable temperature difference of the prototype device reached 6.2 K under a working current of 0.06 A, increased by about 24% as compared with the highest temperature difference of 5 K reported by other groups. Our work demonstrates that the hot-pressing curing process provides an effective approach to fabricate high-performance flexible TE cooling devices with Bi0.5Sb1.5Te3/epoxy thick films through the (000l) preferential orientation.